Download speeds are affected by many things. To help us help you better, please provide the actual speed test results for both PCs, the rated speed of your Internet connection, and the speed test tool or site you are using.
As of right now, using Speedtest.net my DL speed is around 9MB/s on my Desktop, and 12-13MB/s on my Laptop.
My connection is a 10Mb/s plan - which should cap the speed, but in that case. Why am I not hitting the 10MB/s, and why is the laptop exceeding it?